In recent years, as one of the causes of a global warming phenomenon, a greenhouse effect caused by CO2 has been pointed out, and there has been an urgent need, internationally as well, to take measures to protect the global environment. The generation source of CO2 extends over all fields of human activities that burn fossil fuel and the demand for its emission reduction tends to be further intensified. Along with this, for power generation facilities such as thermal power plants that use a large amount of fossil fuel, a way of removing and recovering CO2 of flue gas by bringing the flue gas of a boiler into contact with, for example, amine-based CO2 absorbent, and a way of storing the recovered CO2 without releasing it to the atmosphere have been actively studied.
As a method of removing and recovering CO2 from the flue gas by using CO2 absorbent, there is employed a CO2 recovery system that brings the flue gas into contact with the CO2 absorbent in an absorber, heats up in a regenerator the absorbent that has absorbed CO2 to separate CO2 and regenerate the absorbent, and circulates the regenerated absorbent in the absorber again for reusing. In this CO2 recovery system, in terms of maintaining the water balance of the absorbent within the system, it is desired that the supply of water from the outside of the system be suppressed to a minimum, by using water generated within the system as much as possible. Thus, it is conceived that a regenerator reflux device is installed to condense, as reflux water, water contained in emission gas with which CO2 discharged from the regenerator is entrained, and the reflux water is circulated and reused with, for example, a reclaiming device (Patent Literature 1: Japanese Patent Application Laid-open No. 2012-166139).
However, according to the conception in Patent Literature 1, because the reflux water includes a slight amount of absorption component, it is not possible to efficiently recover the absorption component in the operation of reclaiming. In addition, the measures taken at non-stationary time when the carry-over from the regenerator occurs in some operating conditions are not sufficient.
Furthermore, it is desired that compressor condensate water generated in compressing CO2 in the flue gas discharged from the regenerator be effectively used.